He calls himself an ethical hacker who helps companies and individuals fight back against the bad guys operating online. Over the years, Charles Tendell also has emerged as a commentator in the news media about the threat posed by overseas hackers and is a former co-host of an online radio show about security. But behind the scenes, Mr. Tendell, a Colorado resident and a decorated Iraq War veteran, started a new website called Hacker’s List that allows people to anonymously post bids to hire a hacker. Many users have sought to find someone to steal an email password, break into a Facebook account or change a school grade. Mr. Tendell, 32, who owns a consulting firm in Denver called Azorian Cyber Security, confirmed on Tuesday that he was the sole owner of the website. He said Hacker’s List, which began as something of an “off the cuff idea,” grew far faster than he anticipated. “I never expected it to turn into what it is,” said Mr. Tendell, a graduate of the University of Phoenix who became certified as an information systems security professional and an ethical hacker in 2011. “I was testing the waters and wanted to see if it …